This invention relates to surgical apparatus, and more particularly to surgical apparatus used to occlude or ligate and to divide body tissue.
Ligating and dividing surgical instruments have typically used metal staples, fasteners, or ligatures to ligate organic tissue structures such as blood vessels. One such system is disclosed in Spasiano et al. U.S. Pat. No. 3,955,581. The apparatus described in that patent operates in three stages to positively control the operations of its metal staple-carrying cartridge. The main body of the cartridge is moved forward toward an anvil assembly fixed on the instrument, thereby enclosing the tissue structure within the jaws of the cartridge. A pair of metal staples is then pushed forward to encircle the tissue structure at spaced apart locations. The staples are crimped or clinched against the fixed anvil assembly to ligate the tissue at the locations of the staples. Finally, a knife blade advances to the fixed anvil assembly and divides the tissue structure intermediate the two staples.
Green et al. U.S. Pat. No. 4,086,926 describes another metal staple-carrying cartridge which operates in three stages. Two laterally spaced metal staples are formed around a tissue structure by means of a fixed anvil assembly, thus ligating the tissue structure. A knife then advances to the fixed anvil assembly and divides the ligated structure between the staples. The staple feeding arrangement in that apparatus comprises a pair of belts, each carrying a plurality of staples.
Another ligating and dividing instrument using metal staples as ligatures and a fixed anvil assembly against which the staples are formed is shown in Green U.S. Pat. No. 4,349,028.
For certain surgical procedures, ligatures in the form of fasteners or clips of X-ray-transparent plastic or plastic-like materials may be preferable to X-ray-opaque metal staples. For convenience herein, all such plastic or plastic-like materials will be referred to generically as plastic-like materials. In addition to X-ray transparency, clips of plastic-like material also have the advantage that they can be made biologically absorbable.
Clips of plastic-like material cannot be simply substituted for metal staples in prior ligating and dividing instruments because plastic-like clips cannot be closed by clinching or crimping in the way that metal staples are clinched or crimped. Unlike metal staples, plastic-like clips will not hold a shape to which they are deformed unless parts of the clip mechanically interlock with one another. Thus the means employed in prior ligating and dividing instruments for clinching or crimping metal staples around the tissue are not suitable for use with plastic-like clips. The problems of storing and feeding plastic-like clips are also different from those associated with metal staples.
It is therefore an object of this invention to provide apparatus for ligating and dividing tissue structures which makes use of fasteners or clips of plastic-like material.